CN111734754A

CN111734754A - Multi-plate clutch

Info

Publication number: CN111734754A
Application number: CN202010210506.0A
Authority: CN
Inventors: A·吉恩西斯; M·特勒; W·文德尔; M·埃塞莱; J·克恩; S·奥特; T·司特姆林格; F·尼克尔; D·皮林格尔; H·盖尔布兹; S·罗斯; J·舒尔茨
Original assignee: Miba Frictec GmbH; Kako Co ltd; Muhr und Bender KG
Current assignee: Miba Frictec GmbH; Kako Co ltd; Muhr und Bender KG
Priority date: 2019-03-25
Filing date: 2020-03-24
Publication date: 2020-10-02
Anticipated expiration: 2040-03-24
Also published as: DE102019002212A1; US20200309201A1; DE102019002212B4; CN111734754B; US11274710B2

Abstract

The invention relates to a multiplate clutch for transmitting torque between two shafts and having a locking unit for maintaining a contact pressure acting on clutch disks in a closed clutch. In order to reduce the energy requirement for holding the multiplate clutch in the closed or open state, the locking unit has at least one locking element, at least one guide element, at least one actuating element and at least one pressure element. The guide is arranged to be rotationally fixed and immovable relative to one of the shafts. The locking member is rotatable about its axis and axially displaceable. The locking element and the guide element have interacting control surfaces which are inclined relative to the direction of rotation of the locking element and are used to adjust the locking element into two stop positions. The locking element maintains a contact pressure on the clutch disk in one of the stop positions.

Description

Multi-plate clutch

Technical Field

The invention relates to a multiplate clutch according to the preamble of claim 1.

Background

Torque is transferred between the plurality of shafts using a multi-plate clutch. For this purpose, it is necessary to press the friction plates of the multiplate clutch together in the axial direction. For this purpose, hydraulic pistons are usually used, which are held under pressure if the clutch is closed or the friction linings are pressed against one another. When the multiplate clutch is opened, the hydraulic piston is usually pushed back into its initial position by a spring element. The multiplate clutch is usually designed in such a way that it can be opened or closed in a fail-safe manner in the event of a hydraulic or electrical failure of the transmission in order to separate the drive side and the driven side from one another. Since in such multiplate clutches the actuating pressure must be permanently maintained, in addition to the actuating energy, an energy requirement arises as a result of the hydraulic piston being held in the closed or open state. The pressure chamber in which the hydraulic piston is located and the conveying device are permanently pressurized, which has an adverse effect on the seal. The leakage of the hydraulic medium must also be compensated.

It is also known to provide a locking unit in order to lock the closed multiplate clutch. In such known multiplate clutches, the actuating pressure must also be maintained in the locked state (albeit to a reduced extent) in order to lock the respective blocking element (e.g. ball or ring) and thus optionally hold the multiplate clutch in the open or closed operating state. In addition to the actuating energy, an energy requirement is also required here in order to keep the clutch in the closed or open state.

Disclosure of Invention

The object of the invention is to design the same type of multiplate clutch in such a way that the energy requirement for holding the multiplate clutch in the closed or open state can be reduced.

This object is achieved according to the invention in a multi-plate clutch of the same type by the features of the characterizing portion of claim 1.

The locking unit is designed in such a way that it fully assumes the holding function in the closed or open state of the multiplate clutch. No operating energy is required to maintain the pressing force on the friction plates. This results in a high efficiency of the clutch/brake system. The locking element can be adjusted into two different stop positions. In one of the stop positions, the locking element maintains a contact pressure on the friction plates of the multiplate clutch, while in the other stop position it is moved back so far that it no longer acts on the friction plates, so that the clutch can be opened. In order to adjust the locking element into the different stop positions, the locking element is correspondingly moved axially by means of the actuating element. Since the control surfaces are inclined with respect to the direction of rotation of the locking element, the locking element rotates about its axis in the presence of an axial load in such a way that it can reach the respective stop position.

The locking element forms a mechanical stop by means of which the required contact pressure on the friction lining can be maintained in a simple and reliable manner.

The multiplate clutch according to the invention can be used particularly advantageously in high-speed applications in electric vehicles, in which rotational speeds of between approximately 10000U/min and approximately 50000U/min can occur.

In a simple embodiment, the locking element surrounds the shaft and is mounted on the shaft so as to be axially displaceable and rotatable.

In a preferred embodiment, the locking element is provided with at least one axially extending projection which engages in an axially extending groove of the guide element. Thereby, the locking element and the guide are perfectly oriented with respect to each other. The projections and the grooves manage to enable a reliable axial displacement of the locking element for adjustment into the two stop positions.

In an advantageous embodiment, the groove of the guide is defined by a rib which projects from the outside of the guide.

A compact design of the locking unit results if the guide encloses the one shaft. The guide can be secured in a simple manner against rotation and against axial displacement on the shaft.

Advantageously, the groove of the guide is open at both axial ends. This makes it possible for the projection of the locking element to engage in the groove of the guide at one end and the actuating element at the other end.

In the groove of the guide, there can be a stop against which the projection of the locking element rests in the corresponding stop position.

A simple embodiment results if the stops are arranged at different depths in the groove of the guide. This results in different stop positions of the locking element. If the stop is deep in the grooves, the projections can be pushed correspondingly far into these grooves, so that the locking element projects only slightly axially beyond the guide.

If the stops are not mounted too deeply in the grooves of the guide, the projections of the locking element cannot engage too far into these grooves, so that the locking element projects correspondingly far out of the guide.

In a further advantageous embodiment, the locking element is provided with a further projection which engages in a recess of the shaft.

In order to be able to reach the locking element in different axial positions and to be able to hold it there, the shaft-side recesses are of different depths in the axial direction of the one shaft.

A simple adjustment of the locking element results in that the actuating element is mounted so as to be axially displaceable relative to the one shaft and has a finger which can be pushed into a groove of the guide. If the locking element is to be adjusted into the new stop position, the projection of the locking element can be pushed out of the groove of the guide element by means of the finger.

Advantageously, the end face of the finger of the actuating element and the end face of the projection of the locking element are formed so as to extend obliquely. When the finger of the actuating element pushes the projection of the locking element out of the groove of the guide, the inclined end face of the projection and the finger come into face contact with one another, so that the projection can be reliably displaced in the groove.

Preferably, the end side of the rib of the guide and the end side of the projection of the lock member are disposed obliquely with respect to the rotational direction of the lock member. These inclined end sides form control surfaces with which the rotational direction of the locking element is triggered in the presence of an axial load.

In order to adjust the locking element into the respective locking position, the projection of the locking element is pushed out of the groove of the guide element by means of the finger of the actuating element. The finger of the actuating element is pushed so far that its end face is approximately aligned with the end face of the rib of the guide. Since the end face of the projection of the locking element also extends correspondingly obliquely and the locking element is axially loaded in the direction of the guide, the locking element is rotated about its axis due to the oblique end face, so that the projection of the locking element can then engage in a corresponding groove of the guide or in a recess on the shaft side.

The present disclosure is not to be considered limited to the embodiments described herein, but is to be understood by reference to the drawings and the specification. They are claimed as essential to the invention, even if not the claimed solutions, as long as they are novel individually or in combination with respect to the prior art.

Further features of the invention emerge from the further claims, the description and the drawings.

Drawings

The invention is explained in more detail by means of some embodiments shown in the drawings. In the figure:

fig. 1 shows a schematic representation of a multiplate clutch according to the invention with an integrated locking unit;

fig. 2 shows a schematic representation of a second embodiment of a multiplate clutch according to the invention with an integrated locking unit;

fig. 2a to 2e show different positions of a multiplate clutch and a locking unit during clutching and locking;

fig. 3 shows a schematic representation of a further embodiment of a multiplate clutch according to the invention with an integrated locking unit;

fig. 3a to 3f show different clutch states of the multiplate clutch according to fig. 3;

fig. 4 shows a schematic representation of a further embodiment of a multiplate clutch according to the invention with an integrated locking unit;

fig. 4a to 4d show different clutch states of the multiplate clutch according to fig. 4;

fig. 5 shows the components of the locking unit according to the invention in a schematic view;

FIG. 6 shows an axial cross-sectional view of another embodiment of a multiplate clutch with an integrated locking unit according to the invention;

fig. 7 shows a locking element of the multiplate clutch according to fig. 6 in a perspective view;

fig. 8 shows an end view of the locking element according to fig. 6;

FIG. 9 shows a cross-sectional view along line A-A in FIG. 8;

fig. 10 shows the locking element according to fig. 6 in a perspective rear view;

fig. 11 shows the locking element according to fig. 7 in the mounted position in a side view and partly in a sectional view;

fig. 12 shows the locking element according to fig. 7 in the installed position in a perspective view;

fig. 13 shows a guide of the multiplate clutch according to fig. 6 in a perspective view;

fig. 14 shows the guide according to fig. 13 in a further perspective view;

fig. 15 shows the guide according to fig. 13 in an end view;

FIG. 16 shows a cross-sectional view taken along line A-A in FIG. 15;

fig. 17 shows an actuating element and a piston element of the multiplate clutch according to fig. 6 in a perspective and partially sectional view;

fig. 18 shows the actuating element according to fig. 17 in a perspective view;

fig. 19 shows a sectional view of the actuating element according to fig. 18;

fig. 20 shows the piston element according to fig. 17 in a perspective view;

fig. 21 shows a sectional view of the piston element according to fig. 20;

fig. 22 shows the locking unit in an open multiplate clutch in a perspective and partially sectional view;

fig. 22a shows a locking unit in an open multiplate clutch in a further perspective and partially sectional view;

fig. 23 shows the locking unit in an open multiplate clutch in an axial partial section;

fig. 24 shows in a perspective view an actuating element of the locking unit arranged on the one shaft;

fig. 25 shows, in a diagram corresponding to fig. 23, a locking unit in a closed multiplate clutch;

fig. 26 shows a locking unit in a closed multiplate clutch in a perspective and partially sectional view;

fig. 26a shows the locking unit in a closed multiplate clutch in a further perspective and partially sectional illustration.

Detailed Description

The multiplate clutch described below is characterized in that the locking unit assumes a holding function in the closed or open state of the multiplate clutch. No energy is required to maintain the compressive force. Thereby, the efficiency of the clutch/brake system is improved.

Fig. 6 shows a first embodiment of a multiplate clutch with a locking unit in an axial section. The two

shafts

1, 2 can be coupled to each other by means of a multiplate clutch in such a way that torque can be transmitted from the shaft 1 to the shaft 2. The shaft 1 is provided with an inner friction disk 3, which is connected to the shaft 1 in a rotationally fixed manner. The inner disk 3 is provided with friction linings (not shown). Between the inner friction disks 3 there is an outer friction disk 4 which is connected in a rotationally fixed manner to a clutch housing 5. The inner friction plates 3 and the outer friction plates 4 form a friction plate pack 6.

In order to press the

friction plates

3, 4 against one another, at least one clutch spring 7 is provided. Advantageously, a plurality of clutch springs 7, which may be disk springs, for example, are provided.

The clutch housing 5 with the outer disk 4 is connected in a rotationally fixed manner to the shaft 2.

The shaft 2 has a sleeve 8, on the inner wall of which a clutch housing 5 is arranged.

The two

shafts

1, 2 are accommodated in a housing 9, in which the

shafts

1, 2 are rotatably mounted by means of rolling bearings 10, 11.

At the outlet of the housing 9, the

shafts

1, 2 are each sealed by a shaft seal 12, 13.

In the housing 9, a locking unit 14 is arranged, which has a locking element 15 (fig. 7 to 10) that can be moved axially on the shaft 2, a guide 16 (fig. 13 to 16) that is arranged on the shaft 2 in a rotationally fixed and axially immovable manner, and a sliding sleeve 17 that is arranged axially movably on the shaft 2 as an actuating element.

Said locking unit 14 is characterized in that its actuation in the axial direction is performed by a sliding sleeve 17 in order to move the locking member 15 relative to the guide 16.

The locking element 15 (fig. 7 to 10) has an annular base body 18 which is axially displaceable and rotatable relative to the shaft 2. The base body 18 has axially projecting

projections

19, 20 on one end face thereof. The projections 19 may be wider in the circumferential direction of the base 18 than the projections 20.

The projections 19 are of a larger diameter than the projections 20, and the projections 20 are furthermore spaced apart from one another by a smaller distance in the circumferential direction than the outer projections 19.

The projection 19 has end faces 21, 22 of roof-shaped configuration which extend obliquely opposite one another in the circumferential direction of the base body 18.

While the inner projections 20 have inclined end faces 23 which are arranged in each case inclined in the same circumferential direction.

Between the inner projections 20, rectangular recesses 24 are formed, the base 25 of which is spaced apart from the end face 26 of the base body 18 by an axial distance.

The locking element 15 serves to maintain the pressing force on the

friction plates

3, 4 in the respective axial position.

Here, the locking element 15 interacts with the shaft 2 via its projection 19, on which the locking element 15 is seated in a rotationally and rotationally fixed manner.

The guide 16 (fig. 13 to 16) has a sleeve 27 with which the guide 16 is fastened to the shaft 2. The guide piece 16 is provided on its end facing away from the locking piece 15 with ribs 28 which are arranged distributed on the circumference of the sleeve 27 and project radially beyond the sleeve circumference. The rib 28 extends axially over a part of the axial length of the sleeve 27, starting from one of the end faces 29 of the guide 16.

The ribs 28 each have an inclined end side 30, the inclination of which is the same as the inclination of the end face 23 of the projection 20 of the locking element 15.

Between adjacent ribs 28, axially extending grooves 31 are formed, the width of which corresponds to the width of the projections 20 of the locking member 15. The groove 31 of the guide 16 is open towards the end side 29 of the guide 16.

The sliding sleeve 17 (fig. 17 to 19) is axially displaceable on the shaft 2. The sliding sleeve 17 has fingers 32 which are arranged on the inner side of the sliding sleeve 17 and extend in the axial direction. The fingers 32 project from an end-side ring 51, which is advantageously formed integrally with the fingers 32.

The sliding sleeve 17 is connected to a piston element 52, with which the clutch spring 7 can be actuated in the manner to be described in more detail for closing the multiplate clutch. The piston element 52 (fig. 20 and 21) has an end-side ring 36, which is arranged within the sleeve 8 and from which fingers 53 project axially, which are arranged at a distance from one another along the ring 36. The two end-side rings 36, 51 are connected to one another by means of fingers 53.

The tongues 35 (fig. 17, 20 and 21) project radially inwards from the radially inner side of the fingers 53.

The fingers 53 of the piston element 52 project through the transverse wall 33 (fig. 6) which connects the sleeve 8 with the shaft section 34.

The sliding sleeve 17 forms with the piston element 52 a functional unit with which the clutch spring 7 can be placed under pressure and the locking element 15 can be adjusted between different axial positions.

At least one pressure spring 37 (fig. 6, 22 and 23) is supported on the tongues 35 of the piston element 52. In the exemplary embodiment, a plurality of pressure springs 37 in the form of disk springs are provided, which bear against one another. A pressure spring 37 is supported with its other end on the bottom 38 of an annular recess 54 at the end of the base body 18 of the locking element 15 (fig. 9 and 10), which is seated on the sleeve 27 of the guide element 16 and is supported thereon in the axial direction. The pressure spring 37 therefore manages to load the locking element 15 axially against the guide element 16.

Fig. 22 to 24 show the locking unit 14 in a position in which the

friction plates

3, 4 are not pressed against one another, so that no torque transmission takes place from the shaft 1 to the shaft 2. Here, the locking element 15 is moved axially and assumes a position in which the projection 20 engages in the groove 31 of the guide 16 and the projection 19 engages in a recess 55 provided on the outside of the shaft section 34 (fig. 12). The sliding sleeve 17 is pushed back on the shaft 2 in the axial direction so far that its fingers 32 are out of the grooves 31 of the guide 16 (fig. 23).

The recess 55 is adapted in its contour shape to the projection 19 of the locking element 15. Thus, if the projection 19 of the locking element is embedded in the recess 55, the recess 55 forms an axial stop for the locking element 15. This embedded position of the projection 19 of the locking member 15 can be seen in fig. 24.

Since both the projection 19 of the locking element 15 engages in the recess 55 of the shaft section 34 and the projection 20 engages in the groove 31 of the guide element 16, the locking element 15 is spaced apart from the guide element 16 in this axial position by a minimum distance.

Because the sliding sleeve 17 is pushed back, the clutch spring 7, which is supported axially on the piston element 52, is relieved to such an extent that its force is not sufficient to press the

friction plates

3, 4 against one another, so that a torque can be transmitted from the shaft 1 to the shaft 2. The pressure spring 37 tries to keep the locking element 15 in engagement with the guide element 16 and the shaft section 34.

In order to transmit torque from the shaft 1 to the shaft 2, the

friction disks

3, 4 must be pressed axially firmly against one another in such a way that torque can be transmitted from the shaft 1 to the shaft 2 via the multiplate clutch.

For this purpose, the driver 39 moves the sliding sleeve 17 in the axial direction. In the illustrated embodiment, the drive 39 is a hydraulic drive having an annular piston 40 (fig. 6) which is sealingly movable within the housing 9 in a pressure chamber 41. The pressure line 42 opens into the pressure chamber 41, through which pressure medium can be introduced into the pressure chamber 41. By pressurizing the annular piston 40, the sliding sleeve 17 is moved against the force of the clutch spring 7. As shown in fig. 6, the annular piston 40 acts on a ring 51 of the sliding sleeve 17.

When the sliding sleeve 17 is moved, the fingers 32 bear against the projections 19 of the locking element 15 and push the projections 19 out of the recesses 55 of the shaft section 34. While also pushing the protrusion 20 of the locking member 15 out of the groove 31 of the guide member 16. The inclined end face 23 of the projection 20 reaches a position in which it essentially forms a continuation of the end face 30 of the rib 28 of the guide 16, which is at the same inclination. Since the projections 19 have end faces 21, 22 which are inclined opposite one another, the cooperation of these inclined faces causes the locking element 15 to rotate about its axis when the locking element 15 is loaded by the pressure spring 37. Here, the projections 19 reach into the region of shallow recesses 56 (fig. 12, 26 and 26a) provided between adjacent recesses 55 on the shaft section 34. Due to the oppositely inclined end faces 21, 22, the projection 19 reaches these shallow recesses 56 under the force of the compression spring 37, which recesses are adapted to the shape of the end faces 21, 22 of the projection 19. In this way, the locking element 15 reaches a second axial position in which the locking element 15 is axially displaced relative to the guide 16 in the direction of the friction plate pack 6.

If the sliding sleeve 17 and the piston element 52 are relieved of pressure, the projection 19 reaches into the recess 56. The clutch spring 7 can be pushed back axially only so far that the sliding sleeve 17 and the piston element 52 are loaded (auf Block) until the pressure spring 37 is fully loaded and thus holds the sliding sleeve 17 and the piston element 52 in the operating position in such a way that the

friction disks

3, 4 are held at the pressure necessary for transmitting torque.

The drive 39 is switched off, so that no energy is required to maintain the pressing force on the

friction plates

3, 4.

The pressure spring 37 is designed such that its stiffness is smaller than the stiffness of the clutch spring 7. This ensures that the sliding sleeve 17 loads the clutch spring 7 sufficiently strongly to press the

friction disks

3, 4 firmly against one another for torque transmission.

It goes without saying that, instead of the described drive 39, a further drive device can also be used, with which the sliding sleeve 17 with the piston element 52 can be moved axially in the described manner relative to the guide 16 in order to actuate the locking element 15.

If the multiplate clutch is to be opened again, the sliding sleeve 17 is moved again by means of the drive 39 in such a way that the fingers 32 push the projections 19 out of the recesses 56. Then, due to the interaction of the inclined end faces 21 to 23 of the

projections

19, 20 of the locking element 15, the inclined end faces 30 of the ribs 28 of the guide element 16 and the

recesses

55, 56, the locking element 15 is rotated about its axis to such an extent that the projections 19 reach into the recesses 55 of the shaft section 34 (fig. 11), wherein the pressure spring 37 causes the fingers 32 and therefore also the sliding sleeve 17 to be pushed back. Here, the pressure chamber 41 is relieved, so that the annular piston 40 can be pushed back by the sliding sleeve 17.

The locking element 15 can be adjusted in the manner described into two different axial positions, wherein for determining the axial position the guide 16 and the shaft section 34 are used. In one of the axial positions of the multiplate clutch open, the

projections

19, 20 of the locking element 15 engage in the groove 31 of the guide element 16 and in the recess 55 of the shaft section 34. The other axial position which is assumed when the multiplate clutch is closed is determined in that the projection 19 of the locking element 15 engages in the recess 56 of the shaft section 34. These recesses 56 are significantly shallower than the recesses 55. In this second axial position, the locking element 15 purely mechanically maintains the pressure acting on the

friction plates

3, 4 for torque transmission. The drive 39 can be switched off, so that no pressure medium needs to be fed to maintain the contact pressure in the closed multiplate clutch.

Fig. 1 to 5 show further embodiments of a multiplate clutch in a schematic representation. Wherein the locking element 15 has only a projection 20 which cooperates with the guide element 16 in the two axial positions and is supported thereon.

In the embodiment according to fig. 1, only a clutch spring 7 is provided, with which the

friction disks

3, 4 can be pressed against one another and which at the same time loads the locking element 15 in the direction of its stop position. In the locking position of the locking element 15 when the multiplate clutch is closed, the clutch spring 7 is pretensioned so strongly that the

friction plates

3, 4 can bear against one another with sufficient force and transmit a torque from the shaft 1 to the shaft 2.

With reference to fig. 2a to 2e, the locking process is described in an embodiment, in which two springs are provided according to the embodiment according to fig. 6 to 26. In the embodiment according to fig. 1, locking is also carried out in a corresponding manner.

Fig. 2a shows the locking unit 14 in the open position of the multiplate clutch. The

friction plates

3, 4 are at a distance from each other so that no torque can be transmitted from the shaft 1 to the shaft 2.

As shown in fig. 2a, the projections 20 of the locking element 15 engage in the described manner in the grooves 31 between the ribs 28 of the guide element 16. The axial position of the locking member 15 relative to the guide member 16 can be fixed by means of corresponding stops 49 in the corresponding grooves 31. The sliding sleeve 17 is pulled back so far that its fingers 32 are spaced from the projections 20 of the locking element 15.

The pressure chamber 41 of the drive 39 is unpressurized, so that the annular piston 40 is moved into its starting position by the force of the clutch spring 7 via the sliding sleeve 17.

To synchronize the clutch (fig. 2b), the sliding sleeve 17 is moved axially relative to the guide 16 by means of a drive 39. The clutch spring 7 is thereby loaded in such a way that the

friction plates

3, 4 of the multiplate clutch come into contact with one another. The fingers 32 of the sliding sleeve 17 engage in the grooves 31 of the guide 16 and push the projections 20 of the locking member 15 out of the grooves 31. Because the end faces 32a of the fingers 32 are of roof-shaped design, one of the end flanks 32 a' comes into surface contact with the inclined end face 23 of the projection 20. Since the width of the fingers 32 corresponds to the width of the slots 31, the sliding sleeve is able to move perfectly axially along the guide 16.

As fig. 2c shows, the sliding sleeve 17 is moved by the drive 39 so far that the fingers 32 of the sliding sleeve 17 push the projections 20 of the locking element 15 completely out of the grooves 31 of the guide element 16. The one end flank 32 a' of the finger 32 in the end position of the sliding sleeve 17 substantially forms a continuation of the inclined end side 30 of the rib 28 of the guide 16.

In the state according to fig. 2c, the sliding sleeve 17 is under the maximum actuating pressure of the actuator 39. Due to the

inclined surfaces

23, 30, 32 a', each having the same inclination, the locking element 15 is slightly rotated about its axis under the force of the compression spring 37 in such a way that, when the sliding sleeve 17 is returned, the projection 20 reaches the adjacent groove 31 of the guide element 16.

Fig. 2d shows a situation in which the locking element 15 has been rotated about its axis to such an extent that the projections 20 reach the level of the circumferentially adjacent grooves 31 of the guide element 16. Since the sliding sleeve 17 with its fingers 32 is still in the groove 31 and protrudes from it, the locking element 15 can only be rotated about the axis to such an extent that the projections 20 rest on the adjacent fingers 32 of the sliding sleeve 17.

When the pressure chamber 41 is subsequently relieved, the sliding sleeve 17 is pushed back by the force of the clutch spring 7 so far that its fingers 32 are pushed back in the slots 31 of the guide 16. The projection 20 of the locking element 15 can then reach into the corresponding groove 31 of the guide element 16 under the force of the pressure spring 37. This groove is significantly shorter in the axial direction than the adjacent groove 31 into which the projection 20 was previously inserted. The short depth of the groove 31 is achieved by a stop 46 arranged in the groove, against which the projection 20 rests (fig. 2 e). The stop 46 in the groove 31 advantageously has an inclined stop surface against which the projection 20 rests with its inclined end face 30. The stop 49 also advantageously has a correspondingly inclined stop surface. In the described manner, deeper and less deep grooves 31 are provided alternately along the circumference of the guide 16.

The locking element 15 is held in a position in which it is moved forward in the direction of the multiplate clutch, in which position it locks the sliding sleeve 17 in the position in which it has likewise moved. In this position of the sliding sleeve 17, the clutch spring 7 is loaded to a sufficient extent in order to keep the

multiplate clutches

3, 4 closed. The pressure spring 37 is fully loaded.

In the described manner, the multiplate clutch can also be opened again. In this case, the sliding sleeve 17 is moved again by means of the drive 39 in such a way that the finger 32 pushes the projection 20 of the locking element 15 out of the groove 31 of the guide element 16. By means of the interacting oblique end faces 23, 30, 32 a', the locking element 15 is in turn rotated about its axis in such a way that its projection 20 reaches into the corresponding adjacent deeper groove 31 of the guide element 16. Because these grooves are longer, the locking element 15 is pushed back into the position according to fig. 2a again under the force of the compression spring 37. If the drive 39 is switched off, the sliding sleeve 17 is pushed back into the starting position according to fig. 2 by the clutch spring 7. Since the clutch spring 7 is relieved here, the

friction plates

3, 4 are no longer pressed against one another by the clutch spring 7 to a sufficient extent, so that no torque transmission takes place from the shaft 1 to the shaft 2.

Between the

friction disks

3, 4 there is an expansion spring 50, which presses the

friction disks

3, 4 apart from one another when the pressure is relieved.

Fig. 3 shows an embodiment in which the clutch spring 7 is pretensioned. As a result, the sliding sleeve 17 is pressed against a stop 43, which is arranged on a housing part 44 accommodating the clutch spring 7. As long as the drive 39 for the sliding sleeve 17 is not activated, the clutch spring 7 presses the sliding sleeve 17 with the corresponding mating stop 45 against the stop 43.

The clutch spring 7 is designed such that it cannot press the

friction plates

3, 4 against one another without activating the drive 39.

The compression spring 37 between the locking element 15 and the sliding sleeve 17 is likewise pretensioned.

Fig. 3a shows the situation when the multiplate clutch is open and no actuating pressure is present. The pressure chamber 41 of the drive 39 is unpressurized, the sliding sleeve 17 resting with its counter stop 45 against the stop 43 of the housing part 44 under the force of the pretensioned clutch spring 7. The projection 20 of the locking member 15 is inserted into the deeper groove 31 of the guide member 16. The sliding sleeve 17 is pushed back axially so far that its fingers 32 are spaced apart from the projections 20 of the locking element 15 which project into the groove 31.

To close the multiplate clutch, the gap between the fingers 32 of the sliding sleeve 17 and the projections 20 of the locking member 15 is first closed (fig. 3 b). For this purpose, the annular piston 40 of the driver 39 is put under pressure, so that the sliding sleeve 17 moves accordingly. Mating stop 45 of sliding sleeve 17 disengages from stop 43 of housing member 44.

As soon as the recess is closed, the finger 32 of the sliding sleeve 17 rests with its end-side section 32 a' flat against the inclined end side 23 of the projection 20 of the locking element 15.

Since the sliding sleeve 17 is displaced in the axial direction, the clutch spring 7 presses the

friction plates

3, 4 against one another.

The clutch is synchronized by increasing the pressure further, in that the sliding sleeve 17 continues to move axially in the direction of the locking element 15 (fig. 3 c).

Fig. 3d shows the case in which the multiple plates are synchronized by the clutch and the maximum actuating pressure acts on the sliding sleeve 17. The pressure chamber 41 is at maximum pressure so that the annular piston 40 maximizes the movement of the sliding sleeve 17 against the force of the clutch spring 7.

The fingers 32 of the sliding sleeve 17 press the projections 20 of the locking member 15 out of the grooves 31 of the guide member 16 in such a way that the fingers 32 of the sliding sleeve 17 project slightly beyond the ribs 28 of the guide member 16. Here, the locking element 15 is moved against the force of the pressure spring 37, which thus axially loads the locking element 15 towards its starting position. At the maximum actuating pressure, the inclined end face 23 of the projection 20 of the locking element 15 is located slightly in front of the inclined end face 30 of the rib 28 of the guide element 16.

Since the projection 20 bears with its inclined end face 23 against the correspondingly inclined end-side portion 32 a' of the finger 32 of the sliding sleeve 17 and the locking element 15 is axially loaded by the pressure spring 37 toward the sliding sleeve 17, the locking element 15 is rotated about its axis by the interaction of the inclined faces in such a way that the projection 20 reaches the region of the adjacent groove 31 of the guide 16 with a smaller depth.

This situation is shown in fig. 3 e. The locking element 15 is rotated about its axis to such an extent that the projection 20 is in the level of the adjacent groove 31 of the guide element 16.

The pressure chamber 41 is now made pressureless (fig. 3 f). This results in the sliding sleeve 17 being pushed back by the pretensioned clutch spring 7. Here too, the piston 40 is pushed back. The sliding sleeve 17 also moves the locking element 15 in the axial direction by means of the pressure spring 37. Here, the projection 20 of the locking element 15 reaches into the groove 31 having a smaller depth. The inclined end face 23 of the projection 20 abuts a corresponding stop 46 in the groove 31. The locking element 15 locked in this way serves as a stop for the sliding sleeve 17, so that it cannot be pushed back into its starting position by the clutch spring 7. As fig. 3f shows, mating stop 45 of sliding sleeve 17 is spaced apart from stop 43 of housing part 44 by an axial distance. In the position defined by this stop of the sliding sleeve 17, the clutch spring 7 is pretensioned in such a way that it can press the

friction disks

3, 4 against one another sufficiently firmly to transmit a torque from the shaft 1 to the shaft 2. The compression spring 37 is fully tensioned in this locking position.

To release the multiplate clutch, the sliding sleeve 17 is moved again toward the locking element 15 by pressurizing the piston 40, wherein the fingers 32 of the sliding sleeve 17 push the projections 20 out of the grooves 31 of the guide element 16 in the described manner. By way of the inclined surfaces abutting against one another and the axial loading, the locking element 15 is again rotated about its axis in such a way that the projection 20 reaches the level of the adjacent longer groove 31 of the guide element 16. Subsequently, the drive 39 is switched off, so that the clutch spring 7 can push the sliding sleeve 17 back into the starting position according to fig. 3 and 3a again. The projection of the locking element 15 is pushed back into the longer groove 31, so that the locking element 15 reaches its starting position according to fig. 3 and 3 a. In this starting position, the

friction disks

3, 4 are pressed apart from one another by the expansion spring 50 and the clutch is thus disengaged.

Fig. 4 shows in a schematic configuration an embodiment in which a further pressure spring 47 is provided in addition to the clutch spring 7 and the pressure spring 37. The pressure spring 37 is arranged such that it has a lower spring rate than the clutch spring 7 and the pressure spring 47.

The clutch spring 7 and the pressure spring 47 are separated from one another by a pressure plate 48, which can be moved along the clutch housing 5. The

friction plates

3, 4 are pressed against each other by means of a pressure plate 48.

The sliding sleeve acts on the pressure plate 48 via a pressure spring 47.

Fig. 4a shows the clutch in the open state. The

friction plates

3, 4 have a distance to each other. The projection 20 of the locking member 15 is fitted into the longer groove 31 of the guide member 16. The sliding sleeve 17 is pushed back so far that its fingers 32 are spaced apart from the projections 20.

To synchronize the clutch, the sliding sleeve 17 is moved axially in the described manner by means of the drive 39. Here, the finger 32 reaches into the groove 31 of the guide 16 and moves the projection 20 of the locking piece 15. By moving the sliding sleeve 17, the pressure spring 47 is loaded, which moves the pressure plate 48 against the force of the clutch spring 7. The

friction plates

3, 4 are pressed axially against one another by means of the clutch spring.

As fig. 4b shows, during the synchronization of the clutch, the locking element 15 is moved by the sliding sleeve 17 so far that the projection 20 has not yet been completely pushed out of the groove 31 of the guide element 16. The inclined end face 23 of the projection 20 bears against the inclined end-side section 32 a' of the finger 32 of the sliding sleeve 17.

As described with the previous embodiment, the piston 40 is placed under maximum pressure, thereby moving the sliding sleeve 17 so far that its fingers 32 push the protrusions 20 of the locking element 15 completely out of the grooves 31 of the guide 16. In this position (fig. 4c), the end-side sections 32 a' of the fingers 32 project beyond the inclined end sides 30 of the respectively adjacent ribs 28 of the guide 16. By this overpressure process, the projection 20 is reliably disengaged from the groove 31 of the guide 16. Since the locking element 15 is acted upon by the compression spring 37, which is supported axially on the pressure plate 48, the locking element 15 is rotated about its axis to such an extent on the basis of the inclined end faces 23, 32 a' abutting against one another that the projections 20 reach into the region of the adjacent, less deep groove 31 of the guide element 16.

At the level of the not too deep groove 31, the projection 20 of the locking element 15 bears in the described manner against the finger 32 of the sliding sleeve 17 in said groove 31. Then, according to the previous embodiment, the locking member 15 is oriented axially with respect to the guide member 16, so that the annular piston 40 can now be unloaded. This results in the sliding sleeve 17 being pushed back under the force of the pressure spring 47. At the same time, the projections 20 of the locking element 15 can be moved into the less deep grooves 31 of the guide element 16 under the force of the compression spring 37 until the projections 20 abut against the stops 46 in these grooves 31.

In this locking position, the locking element 15 bears against a pressure plate 48 (fig. 4d), which bears against the locking element 15 under the force of the clutch spring 7. In this stop position, the force of the clutch spring 7 is so high that the multiplate clutch is closed and torque can be transmitted from the shaft 1 to the shaft 2.

In the stop position, the sliding sleeve 17 is pulled back so far that its fingers 32 are spaced apart from the projections 20 of the locking element 15.

If the clutch should be opened again, the sliding sleeve 17 is moved by the driver 39 towards the locking member 15 until the finger 32 pushes the projection 20 out of the less deep groove 31 of the guide 16 until the position corresponding to fig. 4c is reached. The locking element 15 is then rotated again about its longitudinal axis by the force of the compression spring 37 on the basis of the inclined end faces 23, 32 a' which come closer together until the projection 20 comes to bear against the adjacent finger element 32 of the sliding sleeve 17 which projects beyond the adjacent groove. If the sliding sleeve 17 is now pushed back by the relief pressure in the described manner, the projection 20 of the locking element 15 is moved by the spring 37 into the deeper groove 31 of the guide element 16 until the position according to fig. 4a is reached. The clutch spring 7 can then move the pressure plate 48 so far along the clutch housing 5 that the

friction plates

3, 4 are lifted off from one another again under the force of the expansion spring 50.

In the embodiment according to fig. 1 to 5, deep and shallow grooves 31 of the guide 16 are provided in alternating succession. The projection 20 of the locking element 15 is arranged such that it engages only in the deep or only in the shallow groove 31, depending on the rotational position of the locking element 15. The locking element 15 thereby alternately reaches one of the axial positions and the other axial position. The sliding sleeve 17 has a number of fingers 32 equal to the number of grooves 31, so that the projections 20 are pushed out of the respective grooves 31 during each adjustment.

The locking unit 14 of the exemplary embodiment described makes it possible to maintain the pressing force acting on the

friction disks

3, 4 for torque transmission without generating permanent actuating pressure in that the locking element 15 acts as a stop, by means of which the required pressing force on the friction disks is maintained. In the locked state, sufficient contact pressure is applied without energy requirement, wherein a maximum defined torque can be reliably transmitted.

A particular advantage of the locking unit 14 is a simple and robust construction. Only the locking member 15, the guide member 16 and the sliding sleeve 17 and at least one pressure spring are required. The locking element 15 is locked by positive engagement of the

projections

19, 20 of the locking element 15 into the corresponding recesses 56 of the shaft section 34 (fig. 6 to 26) or into the less deep groove 31 of the guide element 16 in order to maintain the contact pressure on the

friction plates

3, 4.

The at least one compression spring can compensate for the geometric tolerances of the three components of the locking unit 14 and the wear of the

friction disks

3, 4, so that the contact pressure is always kept within the permissible range for the torque transmission.

Claims

1. A multiplate clutch for transmitting torque between two shafts, comprising a locking unit for maintaining a contact pressure acting on clutch disks when the clutch is closed, characterized in that the locking unit (14) has at least one locking element (15), at least one guide element (16), at least one actuating element (17) and at least one pressure element (7, 37, 47), the guide element (16) being arranged rotationally fixed and immovable relative to one of the shafts (2), the locking element (15) being rotatable about its axis and axially movable, and the locking element (15) and the guide element (16) having control surfaces (23, 30) which interact with one another, are inclined relative to the direction of rotation of the locking element (15) and are used for adjusting the locking element (15) into two stop positions, and the locking element (15) maintains a contact pressure on the clutch disks (3, 4) in one of the stop positions.

2. The multiplate clutch according to claim 1,

characterized in that the locking element (15) surrounds the shaft (2) on which it is mounted so as to be axially displaceable and rotatable.

3. The multiplate clutch according to claim 1 or 2,

characterized in that the locking element (15) has an axially extending projection (20) which engages in an axially extending groove (31) of the guide element (16).

4. The multiplate clutch according to one of claims 1 to 3,

characterized in that the groove (31) is defined by a rib (28) projecting from the outside of the guide (16).

5. The multiplate clutch according to one of claims 1 to 4,

characterized in that the guide (16) surrounds the one shaft (2).

6. The multiplate clutch according to one of claims 1 to 5,

characterized in that the groove (31) of the guide (16) is open on both axial ends.

7. The multiplate clutch according to one of claims 1 to 6,

characterized in that a stop (46, 49) for the projection (20) of the locking element (15) is provided in the groove (31) of the guide element (16).

8. The multiplate clutch according to one of claims 1 to 7,

characterized in that the stop (46, 49) determines a stop position for the locking element (15).

9. The multiplate clutch according to one of claims 1 to 8,

characterized in that the stops (46, 49) are arranged in the groove (31) of the guide (16) at different depths.

10. The multiplate clutch according to one of claims 1 to 6,

characterized in that the locking element (15) has a further projection (19) which engages in a recess (55, 56) on the shaft side.

11. The multiplate clutch according to claim 10,

characterized in that the shaft-side recesses (55, 56) have different depths in the axial direction of the one shaft (2).

12. The multiplate clutch according to one of claims 1 to 11,

characterized in that the actuating element (17) is mounted so as to be axially displaceable relative to the shaft (2) and has a finger (32) which can be pushed into a groove (31) of the guide (16).

13. The multiplate clutch according to one of claims 1 to 12,

characterized in that the control surfaces (23, 30) are formed by the end sides of the ribs (28) of the guide (16) and the end sides of the projections (20) of the locking element (15).

14. The multiplate clutch according to one of claims 1 to 13,

characterized in that, for adjusting the locking element (15) into the respective stop position, the finger (32) of the actuating element (17) pushes the projection (20) of the locking element (15) out of the groove (31) of the guide (16) such that the end face (30) of the rib (28) of the guide (16) and the end face (32a ') of the finger (32) of the actuating element (17) are substantially aligned with one another, and the locking element (15) can be rotated about its axis on the basis of an axial pressure load by abutting the inclined end face (23) of the projection (20) of the locking element (15) against the inclined end face (32 a') of the finger (32) of the actuating element (17).